Conventionally, many image forming devices such as copy machines and laser printers are structured so that, in the event of a paper jam in a paper transport channel of the device, the upper part of the paper transport channel can be opened by moving some of the members making up the paper transport channel. For example, Japanese Examined Patent Publication No. 8-18724/1996 (Tokukouhei 8-18724, published on Feb. 28, 1996) discloses an image forming device, a side of the main body of which is provided with a side cover integrally provided with some of the structural members making up a paper transport channel, a transport surface of which, when paper jams therein, can be partially exposed by swinging open the side cover, allowing the jammed paper to be removed.
However, in the image forming device disclosed in Japanese Examined Patent Publication No. 8-18724 above, a supporting hinge of the side cover, integrally provided with some of the structural members of a vertical pass of the paper transport channel, is provided in the lower part of the side of the device main body, so that the upper part of the vertical pass of the paper transport channel can be opened out from the device main body. For this reason, if obstructing objects such as books are set next to the device main body on the side cover side, the paper channel cannot be fully opened out from the device main body. Accordingly, problems with this conventional device are that jammed paper is difficult to remove from the paper transport channel, paper sometimes rips, and paper of small size is especially difficult to remove. Moreover, since the paper transport channel turns sharply in the vicinity of a PS (Paper Stop) roller provided in the lower part of the main body, paper easily jams there. However, with the foregoing structure, the lower part of the device main body cannot be exposed by opening the side cover, and thus paper jammed in the lower part of the paper transport channel is particularly difficult to remove.
Further, some conventional image forming devices are structured so that the interior of the device can be exposed to allow performance of operations such as maintenance of the device. For example, Japanese Unexamined Patent Publication No. 8-152756/1996 (Tokukaihei 8-152756, published on Jun. 11, 1996) discloses an image forming device provided with a side cover which can be opened to replace a device in need of replacement, such as a photosensitive drum, developing device, or cleaning device.
Among such image forming devices, some are provided with covers on two adjacent sides of the main body, which can be opened and closed, and which have an order of opening and closing. Structures for opening and closing covers in an image forming device of this type include the following.
For example, Japanese Unexamined Patent Publication No. 8-152756 above and Japanese Unexamined Utility Model Publication No. 6-73005/1994 (Jitsukaihei 6-73005) disclose an image forming device having an upper cover provided in the top and a side cover provided in the side of the main of the image forming device, in which one end of the side cover, which can be opened and closed, is provided with projections which engage with holes provided in the side of the device main body. The device main body, on the other hand, is provided with shielding members, etc. which shield the holes. By the action of closing the upper cover, the shielding members, etc. are pressed and moved, thus releasing shielding of the holes. After shielding of the holes has been released, the side cover can be closed.
However, in conventional structures like the foregoing, the upper cover and the side cover provided in adjacent sides of the device are given an order of opening and closing by means of separate structural members such as shielding members. Accordingly, not only is the number of members is increased, but the structure is also complicated, and cost is increased.